Conventionally, various power generation devices which use gravitational energy are proposed. A typical power generation device is a hydraulic power generation device which generates power by rotating a turbine using water discharged from a dam or flowing water of a river. However, such a hydraulic power generation device requires large-scale construction to build a dam and has a problem that building and manufacturing costs are high. Further, the amount of water in a dam or a river changes depending on the weather or the season, and therefore there is a problem that it is difficult to stably supply power when a water shortage occurs.
Hence, the inventors of this application proposes as a new power generation device which uses gravitational energy a ring power generation system which has a rotation driving motor, a ring body which is coupled to this motor to be rotated, a plurality of power generation motors which are arranged at equal intervals on this ring body and weight bodies which are hung from the motor rotary shafts of these power generation motors in Japanese Patent Application Laid-Open No. 2005-39949 (Patent Literature 1). According to this Patent Literature 1, the power generation motor rotates with the ring body and the motor rotary shaft keep the same posture by the hung weight body, so that the motor body and the motor rotary shaft of the power generation motor relatively rotate and it is possible to generate power.
That is, the ring power generation system is a electrical generator which has never been heard of and which can rotate the power generation motors using gravitational energy which works on the weight bodies and convert the rotation into electric energy.
Further, the ring power generation system provides an advantage that manufacturing cost is low since commercial motors can be used for the rotation driving motor and the power generation motors. Furthermore, the rotation driving motor causes rotation, so that fluctuation is not caused by the weather or the season.
Still further, a plurality of power generation motors are arranged at equal intervals on a ring body, so that weights of the opposing power generation motors cancel each other about the rotary shaft of the ring body and energy which resists the gravitational force is not required. Consequently, it is possible to provide advantages that energy required to rotate the ring body and the like is small and running cost is low.